import pino from 'pino';
import type { LogForwarder, LogEntry } from '../services/log-forwarder.js';

let _logForwarder: LogForwarder | null = null;

/**
 * Register a LogForwarder instance.
 * Once registered, all loggers created via `createLogger` will
 * also forward their output to the cloud backend.
 */
export function setLogForwarder(forwarder: LogForwarder): void {
  _logForwarder = forwarder;
}

export function createLogger(name: string, level = 'info') {
  const logger = pino({
    name,
    level,
    transport:
      process.env.NODE_ENV !== 'production'
        ? { target: 'pino-pretty', options: { colorize: true } }
        : undefined,
  });

  // Wrap the logger to also forward logs when a forwarder is set.
  // We hook into Pino's internal write by using `onChild` isn't available,
  // so we use a proxy on the logging methods.
  return new Proxy(logger, {
    get(target, prop, receiver) {
      const value = Reflect.get(target, prop, receiver);

      // Intercept logging methods: trace, debug, info, warn, error, fatal
      if (
        _logForwarder &&
        typeof prop === 'string' &&
        ['trace', 'debug', 'info', 'warn', 'error', 'fatal'].includes(prop) &&
        typeof value === 'function'
      ) {
        return (...args: unknown[]) => {
          // Call original
          (value as (...a: unknown[]) => void).apply(target, args);

          // Forward to the cloud
          try {
            const levelNum = target.levels.values[prop] ?? 30;
            let msg = '';
            let extra: Record<string, unknown> = {};

            if (typeof args[0] === 'string') {
              msg = args[0];
            } else if (typeof args[0] === 'object' && args[0] !== null) {
              extra = args[0] as Record<string, unknown>;
              if (typeof args[1] === 'string') {
                msg = args[1];
              }
            }

            const entry: LogEntry = {
              level: levelNum,
              time: Date.now(),
              msg,
              name,
              ...extra,
            };

            _logForwarder!.ingest(entry);
          } catch {
            // Never let forwarding break the app
          }
        };
      }

      return value;
    },
  });
}

export type Logger = pino.Logger;